The invention relates to a process for the production of a cation exchanger which is particularly suitable for the treatment of waste water.
The treatment of municipal and industrial waste water is becoming an increasing problem, especially in industrialized countries. A major problem is encountered when the waste water contains refractory components, i.e., components that cannot be biologically decomposed. It is therefore technologically important to develop processes which give a high efficiency at relative low cost for the treatment of waste water which besides protein and heavy metals contains refractory components. Proteins can be treated on biological units, but often these materials are so valuable that it would be natural to consider a recovery process.
Proteins, polypeptides and amino acids can be removed by chemical precipitation. As precipitants are used lignin sulphuric acid and dodecylbenzene sulphonic acid, and others.
However, only very high molecular weight proteins are precipitated, and compounds such as proteins which medium and lower molecular weight, polypeptides and amino acids are not removed by this process.
It would therefore be desirable to have an ion exchanger available which can remove such compounds and can therefore be used for treatment of waste water, which has been subjected to the precipitation treatment. Examples of waste water for which such a combined treatment may be advantageous is such from fish filletting factories, dairies, slaughterhouse and other food processing plants. This removal is furthermore of interest for recirculation of water in fish farms.
A number of cellulose ion exchangers are already on the market. Examples are cellulose sulphate esters produced by reacting cellulose with SO.sub.3, and also cellulose phosphate esters. These are capable of solving the above-mentioned problem, but all these ion exchangers are prohibitively expensive.